Re: creating netdev queues on the fly?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Le jeudi 10 novembre 2011 à 17:26 +0100, Johannes Berg a écrit :
> On Thu, 2011-11-10 at 15:35 +0100, Eric Dumazet wrote:
> 
> > > So to get to my question: What if we could create netdev queues on the
> > > fly?
> 
> > In term of qdisc management I believe its a bit complex if we start to
> > dynamically add netdev queues :)
> 
> Yeah I was thinking that would be the problematic part.
> 
> > My first idea would be to extend Qdisc management so that a device can
> > callback qdisc when a frame is finaly delivered / consumed / discarded.
> > 
> > We currently only have qdisc->enqueue() and qdisc->dequeue(), we could
> > add qdisc->deliver_callback(skb)
> > 
> > You keep devices as they are, with a netdevqueue per hardware queue.
> > 
> > Then, using a Qdisc like existing ones, but with a limit of
> > outstanding(given to device but not yet consumed) packets per class.
> > 
> > external tc classifier would deliver a hash/index depending on remote
> > station.
> 
> So basically you'd have a class for each station? Or a class for each
> station/AC? That's a lot of classes rather than queues, are they
> pre-allocated, or does it not matter? Overall that sounds like a good
> approach.

They could be statically allocated in a stochastic fashion (Sorry, SFQ
is one of my favorite qdisc, very light in memory/cpu and yet powerful)

net/sched/sch_sfq.c

Of course, HFSC / DRR are considered more flexible, but eat _much_ more
memory.

http://people.netfilter.org/kaber/shaping

You declare a hash divisor of 1024 to map one station to one class
(Might have hash collision of course...)

Each active slot contains a local queue to one remote station.
Each queue can be pfifo or whatever smart qdisc (sfq, or a more flexible
qdisc)

Then you use a filter to select the appropriate class :

tc filter add dev ${dev} protocol all pref 1 parent $handle handle 1 \
	flow hash keys remote_station divisor 1024



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Kernel Discussion]     [TCP Instrumentation]     [Ethernet Bridging]     [Linux Wireless Networking]     [Linux WPAN Networking]     [Linux Host AP]     [Linux WPAN Networking]     [Linux Bluetooth Networking]     [Linux ATH6KL Networking]     [Linux Networking Users]     [Linux Coverity]     [VLAN]     [Git]     [IETF Annouce]     [Linux Assembly]     [Security]     [Bugtraq]     [Yosemite Information]     [MIPS Linux]     [ARM Linux Kernel]     [ARM Linux]     [Linux Virtualization]     [Linux IDE]     [Linux RAID]     [Linux SCSI]